-5-
Heat Sinking
Electronic components such as transistors, IC’s, and
diodes can be damaged by the heat during soldering.
Heat sinking is a way of reducing the heat on the
components while soldering. Dissipating the heat
can be achieved by using long nose pliers, an
alligator clip, or a special heat dissipating clip. The
heat sink should be held on the component lead
between the part and the solder joint.
Soldering Surface Mount Components
1. Using tweezers, place the surface mount
component on the PC board pads and secure in
place with tape (see Figure 7A).
2. Apply a small amount of solder to the soldering
iron tip. This allows the heat to leave the iron and
flow onto the foil.
3. Place the iron in contact with the PC board foil.
Apply a small amount of solder simultaneously to
the foil and the component and allow them to
melt the solder.
4. Remove the iron and allow the solder to cool. The
solder should have flowed freely and not lump up
around the component.
5. Remove the tape and solder the other side of the
component.
When soldering the transistors, diodes and
integrated circuits, the following procedure may
be used:
1. Place the component on the PC board pads and
secure in place with tape.
2. Apply a small amount of solder to the soldering
iron tip.
3. Place the soldering iron tip on top of the
component lead to be soldered and apply solder
simultaneously to the lead and the PC board foil.
4. Remove the iron and allow the solder to cool. The
solder should have flowed freely and not lump up
around the component.
After a component is completely soldered, each
solder joint should be inspected with a magnifying
glass. If the solder has not flowed smoothly, a bad
solder joint is indicated. This occurs when the
component and pad have not been heated sufficiently.
To correct, reheat the connection and if necessary
add a small amount of additional solder.
Another way to solder surface mount components is
as follows:
1. Apply a small amount of solder to the soldering
iron tip as shown in Figure 7B.
2. Using tweezers, hold the component on the PC
board pads.
3. Apply the soldering iron simultaneously to the
component and pad and allow the solder to flow
around the component.
4. Remove the soldering iron and allow the
connection to cool.
Tweezers or Pliers
Solder
Soldering Iron
Surface Mount Component
Heat Sink
(this can be ordered as part of
Elenco’s Solder Ease Kit Model
SE-1 - see Page 6).
Soldering Iron
Solder
Heat Sensitive
Component (Diode)
PC Board
Figure 7B
Figure 6
Tape
Iron
Solder
Figure 7A
